service postgresql initdb

service postgresql start

sudo -u postgres psql .....

postgres=#.....

If all you are doing is writing code, that's sufficient on an rpm based platform. On Debian, use apt-get instead. On Windows use the 1 click installer.

PostgreSQL comes with a default user and a default database, so the criticism on this thread is a bit..... incorrect.

Now it is true you have to set up a system user if you are compiling PostgreSQL from source. However, that's really optional in most cases unless the code you are writing is, well, a patch to PostgreSQL.......